LOS ANGELES – Angelina Jolie wrote the foreword for her ex-husband, Billy Bob Thornton's new memoir, "The Billy Bob Tapes: A Cave Full of Ghosts," a rep for HarperCollins confirmed to Us Weekly.

The news comes amidst rumors that Thornton's new film may be based on his wild romance with Jolie, his fifth wife. Jolie is now in a highly-publicized relationship with Brad Pitt, with whom she has six children.

Thornton and Jolie married in 2000, despite their 20 year age difference, and quickly distinguished themselves as one of the most bizarre couples in Hollywood, known for wearing vials of each other's blood around their necks.

While they split in 2003, there appears to be no bad blood between the famous exes.

In 2010, Thornton said of Jolie, "We talk every now and then. She seems to be doing very well directing her own movie, which I am so proud of her for. She's real smart, and very creative, and I think it's a great job for her."

Thornton, 56, was referring to "In the Land of Blood and Honey," the Bosnian war love story that Jolie, 36, wrote and directed.

Since 2003, Thornton has been in a relationship with makeup artist Connie Angland, with whom he had a daughter.

Jolie picked up with Pitt in 2005 and the Hollywood power couple has been going strong ever since.